1. Field of the Invention
The present teachings are directed towards a method for producing hydrocarbons by a Fischer-Tropsch mechanism and the catalysts for the method. The hydrocarbon producing method includes providing a catalyst of a manganese oxide-based octahedral molecular sieve nanofibers with at least one of iron, cobalt, nickel, copper, manganese, vanadium, zinc, and mixtures thereof, and further containing an alkali metal. The formation of iron carbides and cobalt carbides by exposing the catalyst to conditions sufficient to form those carbides is also taught. After the catalyst has been appropriately treated, a carbon source and a hydrogen source are provided and contacted with the catalyst to thereby form a hydrocarbon containing product. The characteristics of the hydrocarbon products can be controlled by the formulation and treatment of the catalyst.
2. Discussion of the Related Art
Production of clean fuel and fine chemicals via Fischer-Tropsch (“FT”) synthesis has attracted interest in both academia and industry. Catalysts (Co, Fe, Ru, and Ni) for the conversion of CO2 supported on inert silica, alumina, zeolites, and carbon nanotubes have been developed for FT synthesis. The hydrocarbon products of these catalysts are mainly paraffins. Additional manganese oxides have been used to increase the selectivity towards long chain olefins, for instance, alkenes, but these manganese oxides decreased overall activity due to their enrichment on the catalyst surfaces.
K-OMS-2 (KMn3+Mn4+7O16) is composed of 2×2 edge-shared MnO6− octahedral chains, which are corner shared to form one-dimensional tunnels (4.6×4.6 A), with K+ ions located in the tunnels. The unique expandable structure and components suggest that K-OMS-2 nanofibers can be suitable templates for engineering design of FT catalysts. The high surface area, 60-150 m2/g OMS-2 nanofibers can be supports for incipient wetness impregnation (“IWI”) of Co, Fe, and Cu-based catalysts. Additionally, the mixed valence K-OMS-2 structure can be selective oxidation catalysts.